1. Field of the Invention
The present invention relates generally to a method and an apparatus for manufacturing a spunlaced non-woven fabric (fiber-entangled non-woven fabric). More particularly, the invention relates to a method and an apparatus for manufacturing a non-woven fabric, which can form a predetermined pattern on a surface of the non-woven fabric.
2. Description of the Related Art
Conventionally, on-woven fabrics have been used as wet tissue paper, cleansing tissue paper, wiping sheet for comfortably wiping baby""s hip, cleaning sheet and so forth, which are brought into direct contact with the human skin or hand, and therefore require soft feeling and pleasant contact feeling.
Therefore, conventionally, relatively soft spunlaced non-woven fabrics have been widely used as such sheets. The spunlaced non-woven fabric is preferably processed to have protrusions and recesses arranged in a predetermined pattern so as to provide bulkiness for easy holding by hand or so as to improve cleaning effect. In the prior art, generally, such protrusions and recesses arranged in a predetermined pattern are formed by clamping a spunlaced non-woven fabric in a dry condition between a pair of heated embossing rolls so that the pattern of the embossing rolls is transferred to the non-woven fabric by heat and pressure.
However, in case where the spunlaced non-woven fabric is patterned in a dry condition by heating and pressing it with the heated embossing rolls, the non-woven fabric tends to restore its original flat surface when wetted with liquid or water. Therefore, the difference in level between the protrusions and recesses of the patterned surface may be reduced so that the pattern may fade or completely disappear. In this case, moreover, large tension force is locally applied to the non-woven fabric thus clamped between the embossing rolls to thereby enlarge the distance (gap) between adjacent fibers. Therefore, the fiber density is locally lowered to form thin portions in the non-woven fabric. This results in decreasing bulkiness and tensile strength.
Here, moisture may be applied to the non-woven fabric which has been once dried for transferring the pattern of the embossing rolls to the wet non-woven fabric by heating and pressing it with the embossing rolls. However, even in this case, similarly to embossing under a dry condition, the non-woven fabric in a wet condition may be locally stretched to locally lower the fiber density as set forth above.
The present invention has been worked out in view of the problem set forth above. Therefore, it is an object of the present invention to provide a method and an apparatus for manufacturing a non-woven fabric, whereby a predetermined pattern can be transferred without lowering strength of the non-woven fabric and the pattern transferred to the non-woven fabric can be well maintained even upon use in a wet condition.
According to a first aspect of the present invention, there is provided a manufacturing method of a non-woven fabric comprising the steps of:
forming a fibrous web on an outer peripheral surface of a wire net transporting belt circulating;
forming a non-woven fabric by applying water jets to the fibrous web on the outer peripheral surface of the wire net transporting belt for entangling fibers; and
transporting the non-woven fabric to be opposed to a forming body having a predetermined pattern, and applying water jets to the non-woven fabric from the side of an inner peripheral surface of the wire net transporting belt or another wire net transporting belt following the wire net transporting belt for urging the non-woven fabric onto the forming body for transferring the pattern of the forming body to the non-woven fabric.
According to a second aspect of the present invention, there is provided a manufacturing method of a non-woven fabric comprising the steps of:
forming a fibrous web on an outer peripheral surface of a wire net transporting belt circulating; and
transporting the fibrous web to be opposed to a forming body having a predetermined pattern, and applying water jets to the fibrous web from the side of an inner peripheral surface of the wire net transporting belt for urging the fibrous web onto the forming body for entangling fibers of the fibrous web for forming a non-woven fabric and in conjunction therewith for transferring the pattern of the forming body to the non-woven fabric.
In each manufacturing method, the forming body may be a member having a plurality of openings, and a pattern of the openings may be transferred to the non-woven fabric. Alternatively, the forming body may be a net, and a pattern of the net may be transferred to the non-woven fabric.
In the fibrous web forming step, preferably, a raw material, in which the fibers are mixed with a liquid, is provided on the wire net transporting belt. The manufacturing method may further comprise a drying step for drying the non-woven fabric having the pattern transferred thereto.
According to a third aspect of the present invention, there is provided a manufacturing apparatus of a non-woven fabric comprising:
a wire net transporting belt circulating;
fiber supply me ns for supplying material fibers on an outer peripheral surface of the wire net transporting belt and forming a fibrous web on the outer peripheral surface of the wire net transporting belt;
first water jet means for applying water jets to the fibrous web from the side of the outer peripheral surface of the wire net transporting belt for entangling the fibers of the fibrous web and forming a non-woven fabric;
a forming body having a predetermined pattern to be opposed to the non-woven fabric on the outer peripheral surface of the wire net transporting belt; and
second water jet means for applying water jets to the non-woven fabric from the side of an inner peripheral surface of the wire net transporting belt for urging the non-woven fabric onto the forming body for transferring the pattern to the non-woven fabric.
According to a fourth aspect of the present invention, there is provided a manufacturing apparatus of a non-woven fabric comprising:
a wire net transporting belt circulating;
fiber supply means for supplying material fibers on an outer peripheral surface of the wire net transporting belt and forming a fibrous web on the outer peripheral surface of the wire net transporting belt;
a forming body having a predetermined pattern to be opposed to the fibrous web on the outer peripheral surface of the wire net transporting belt; and
water jet means for applying water jets to the fibrous web from the side of an inner peripheral surface of the wire net transporting belt for urging the fibrous web onto the forming body for entangling the fibers of the fibrous web for forming a non-woven fabric and in conjunction therewith for transferring the pattern to the non-woven fabric.
In each manufacturing apparatus, the forming body may be a drum or circulating belt having a plurality of openings on a surface thereof. Alternatively, the forming body may be a drum having a net on surface thereof or a circulating belt made of a net.
Preferably, the fiber supply means supplies a raw material, in which the fibers are mixed with a liquid, to the wire net transporting belt. The manufacturing apparatus may further comprise drying means located downstream of the forming body for drying the on-woven fabric having the pattern transferred thereto.
In the manufacturing method and apparatus of the present invention, the patter of the forming body is transferred to the non-woven fabric by applying water jets to the non-woven fabric, after or simultaneously with formation of the non-woven fabric. In the non-woven fabric thus patterned, the gap between adjacent fibers in the protrusions of the patterned non-woven fabric is no enlarged to thereby prevent the fiber density thereof from being locally lowered. Therefore, the pattern can be transferred while maintaining sufficient thickness over the entire sheet. As a result, the non-woven fabric having the pattern transferred thereto has sufficient strength.
On the other hand, if the pattern is transferred to the non-woven fabric in a wet condition and thereafter the non-woven fabric is dried, the patterned surface can be well maintained without causing flatting thereof. Also, since forming force of the patterned surface is applied by water jets to provide softness to both the protrusions and recesses of the patterned sheet, the resulting sheet can provide soft feeling as a whole. Furthermore, the patterned non-woven fabric once dried can be suitably used as wet sheet by wetting it again. This is because the difference in level between the protrusions and recesses of the patterned surface is restored by wetting it again, so that the pattern is emphasized in the wet condition as compared with that in the dry condition. Therefore, even in a wet condition, the patterned surface of the non-woven fabric can be well maintained.